.jstb_ext_submenu {
  position: absolute;
  width: 300px;
  background-color: #F7F7F7;
  border: 1px solid #ccc;
  box-shadow: 5px 5px 5px #ccc;
}

.jstb_ext_submenu button {
  width: 100%;
  text-align: left;
}